Rubinfeld told AFP it clearly “is a terrorist act” as a man had been seen driving up and entering the museum before opening fire inside and running off.

Three people were killed in the shooting and a fourth was in critical condition. Twelve people were being treated for shock, according to local sources.

“Two women and one man are dead, a third person is in hospital,” Interior Minister Joelle Milquet said at the scene. “We don’t yet know if they were tourists or staff, they haven’t been identified.”

Asked whether she believed it was an anti-Semitic attack, she said it was too early to say as a police and judicial inquiry was under way but that given the target “there are strong grounds for presuming so”.

One man was reported in custody after the attack, but he was later ruled out as a suspect.

Milquet said the government had moved to increase protection at Jewish buildings as well as the Israeli embassy.

The country’s foreign minister, Didier Reynders, tweeted Saturday that he was “shocked by the murders committed at the Jewish museum.”

“I am thinking of the victims I saw there and their families,” he said.

The La Libre newspaper said on its website that an Audi had driven up and parked outside the museum, and that both a passenger and the driver had gotten out.

It said the driver placed two bags on the ground and then opened fire on bystanders before driving off.

Police and emergency services were at the site, which was blocked off in the Belgian capital.

Forensic experts examine the site of a shooting at the Jewish museum in Brussels, Saturday, May 24, 2014. (Photo credit: AP/Yves Logghe)

The Jewish Museum of Belgium, which was not answering calls, is located in the heart of the Sablon district which is home to the city’s top antique dealers. The area is a popular weekend haunt for shoppers.

The museum is not run by the Jewish community, and is therefore open on Saturdays. There were visitors at the museum at the time of the shooting.

The head of Belgium’s Jewish Consistory told La Libre that “is is probably a terrorist act. For us it is an extremely serious act.”

He said the museum had received no recent threats and that its staff “are in shock”.

The police had a “serious tip”, he added, amid reports that a bystander had given the police the car’s registration number.

The Sablon area consists of cobblestoned streets with numerous antique shops, trendy cafes and museums, including the Jewish Museum. The attack happened during a three-day jazz festival in the neighborhood, and came on the eve of national and European Parliament elections.

Viviane Teitelbaum, a Jewish member of the Brussels legislature, said anti-Semitic attacks reached a peak in the early 1980s but had dropped off before a recent rise in anti-Jewish sentiment.

“It has been a very difficult place to live” for Jews, she said, adding that many young people are leaving the country. She added some 40,000 Jews live in Belgium, half of whom reside in Brussels.